Synergistic activation of dendritic cells by combined Toll-like receptor ligation induces superior CTL responses in vivo

Blood. 2006 Jul 15;108(2):544-50. doi: 10.1182/blood-2005-10-4015. Epub 2006 Mar 14.

Abstract

Toll-like receptors (TLRs) are able to interact with pathogen-derived products and their signals induce the coordinated activation of innate and adaptive immune mechanisms. Dendritic cells (DCs) play a central role in these events. As the different TLRs are able to trigger MyD88/TRIF-dependent and -independent signaling pathways, we wondered if the simultaneous activation of these signaling cascades would synergize with respect to DC activation and induce superior cytotoxic T-lymphocyte (CTL) activity in vivo. We observed that indeed the combined activation of MyD88-dependent and -independent signaling induced by TLR7 and TLR3 ligands provoked a more rapid and more sustained bone marrow-derived DC (BMDC) activation with regard to the secretion of proinflammatory cytokines, like IL-6 and IL-12p70, and the expression of costimulatory molecules like CD40, CD70, and CD86. Furthermore, in the presence of combined TLR ligand-stimulated DCs, CD4(+) and CD8(+) T cells were insensitive toward the inhibitory effects of regulatory T cells. Most importantly, peptide-loaded BMDCs stimulated by TLR ligand combinations resulted in a marked increase of CTL effector functions in wild-type mice in vivo. Thus, our results provide evidence that unlocking the full potential of DCs by advanced activation protocols will boost their immunogenic potential and improve DC-based vaccination strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Bone Marrow Cells
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism
  • Immunity
  • Ligands
  • Membrane Glycoproteins / immunology
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Myeloid Differentiation Factor 88
  • Signal Transduction
  • T-Lymphocytes
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Regulatory
  • Toll-Like Receptor 3 / immunology
  • Toll-Like Receptor 3 / metabolism
  • Toll-Like Receptor 7 / immunology
  • Toll-Like Receptor 7 / metabolism
  • Toll-Like Receptors / immunology*
  • Toll-Like Receptors / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Ligands
  • Membrane Glycoproteins
  • Myd88 protein, mouse
  • Myeloid Differentiation Factor 88
  • Tlr7 protein, mouse
  • Toll-Like Receptor 3
  • Toll-Like Receptor 7
  • Toll-Like Receptors